Method for polymerizing olefins



Patented Dec. 5, 1950 I um'rso S TA'lE Memoir roa Sherman S. Shailer,Baytown, and

s 3mm orr cs Bradshaw I.

Armendt, Pelly, Tex, allgnors to Standard Development Company, acorporation of Delaware Application November 2:, 1m, Serial n sumo 9 mm;(oi. zoo-sari z tact to form a resultant stream wherein sprayins ormisting of the streams is greatly reduced or prevented. Morespecifically, it is an object of the present ar -invention to polymerizehydrocarbons including 'thefstcps' of forming a stream by contacting I astream of olefin-containing feed stock with a stream of medal-Craftsmetallic halide catalyst, the two streams flowing substantiallyconcurrent- 10 17' admixture and the resultant liquid ence of aFriedel-Crafts metallic halide catalyst. 1

As an example of such a process. the polymer known as butyl rubber isoften produced by reacting an admixture of isobutylene and butadiene 0risoprene in the presence of a metallic halide, such as aluminum chlorideor boron triiluoride. The reaction may be conducted continuously at lowtemperatures in a dilute solution using methyl chloride as a diluent.Other alkyl halides may be employed as solvents or diluents for thereagents.

stream being surrounded by a concentric stream 'of gas flowing atsubstantially the same velocity as the liquid stream to preventspattering or misting of the liquid stream.

Inthe process of the present invention a stream I of chilled feedhydrocarbon, which is preferably in the form of a solution of oleflns inmethyl chloride or a solution of olefin and diolefln in methyl chloride,is brought into contact in space 20 with a chilled solution ofFrledel-Crafts metallic When reacting the oleilns or mixture of olefinsY mixing the hydrocarbon feed stock and catalyst and discharging it in afree space within a reaction vessel is by the use of a jet reactor"which is an arrangement of concentric nozzles by which a stream ofhydrocarbons and a stream of fluid catalyst are brought into contact inspace. Such jet reactors are known to the art, and a desirablearrangement is disclosed in U. S. Patent application Serial No. 491,028,filed in the name of John D. Calfee et al. on June 16, 1943, now Patent2,491,710. It is conventional to arrange one or If a polymer is formedhalide catalyst. such as a solution of aluminum chloride in methylchloride. andthe two streams admixed to form a resultant liquid streamand the resultant stream of reactants surrounded with a concentric massof gas moving in the same direction as the liquid stream and withsubstantially the same velocity for a sufllcient interval of time toallow the polymerization reaction to proceed substantially as far asdesired in order to produce a polymer of the desired characteristics.The stream of liquid reactants is kept from spattering or misting by theconcentric mass of gas and prevents deposition of polymer on the sidesof the vessel defining the reaction zone.

more jet reactors in a relatively large reaction zone with the reactantmixture produced by the jet or jets first projected into free space.where a polymer is allowed to form and with a quenching zone, containinga quenching liquid, such as warm water or alcohol, arranged into whichthe polymer is quenched in order to terminate the polyastream of fluidcatalyst are brought into con- After the reactants have been allowed topolymerize in the free space, the major portion of the concentric massof gas is removed from the reaction zone andthe reactants dischargedinto a quenching zone. v

In the practice of the present invention, it is preferred to employ anelongated reaction vessel, to discharge the stream of reactantssurrounded by a concentric stream of gas into one end of the vessel, tomaintain a second zone of lower pressure some distance from thepoint atwhich the liquid reactants are admixed and along the axis of the streamof the reactants and to withdraw the major portion of the blanketingconcentric mass of gas from the reaction zone at this point and tomaintain in a third zone at a lower pressure than the second zoneayquenching liquid for quenching the polymer and to remove from thethird zone the remaining portion of the blanketing gas as well as vaporsfrom the quenching liquid.

Otherobjects and advantages of the present invention may be seen from areading of the following description taken with the drawing in assaoseFig. 1 shows an embodiment suitable for carrying out the presentinvention and Fig. 2 is a fragmentary view showing in greater detail anozzle arrangement suitable for use in the embodiment of Fig. 1.

Turning now to the drawing, it will be seen that an elongated reactionvessel H is provided with an assembly of nozzles l2 in the upper end ofthe vessel and pointed downwardly so that the axis 01 the streamprojecting from the plurality of nozzles l2 lies approximately along thevertical axis of vessel II.

The assembly of nozzles is shown in greater detail in Fig. 2. Thesenomles include an inner tube- It and a second tube It concentric withtube l2 and an outer tube l concentric with the other tubes. Tube I3 isconnected with inlet line I! which serves to supply liquid catalyst tothe reaction vessel. A second tube It is connected through inlet line I!to supply a mixture oi hydrocarbon feed stock to the reactor. An inletline It is arranged to supply gas to the space between concentric tubesl4 and It.

It will be seen that the assembly I2 is arranged in the upper end ofvessel II and fluids 'passed into assembly l2 are discharged downwardlyinto vessel II. The streams of liquid passed into nozzle assembly l2through inlet lines It and I! are caused to flow in a parallel directionand these two streams are mixed intimately in space to form -a resultantliquid reactant stream. In the nozzle assembly a gaseous stream is alsoformed with its direction of iiow parallel with the flow of the twoliquid streams and this gaseous stream is formed so that it isconcentric with and surrounds the resultant reaction stream and hassubstantially the same velocity as the resultant stream.

Vessel II is divided into a plurality of zones by a series of bames I9,20, 2| and 22. Each oi the bailles is in the shape of an annulus with anopen ng through the center of the annulus sumciently large to .allow thestream of reactants and gas to flow downwardly through the vessel. Thebaflle extending laterally across the vessel divides it into a pluralityof zones which are designated, reading from the top to the bottom of thevessel, as, zone; A, B, C, D and E.

Vessel H is arranged to have a pool of quenching liquid maintained inthe lower portion thereof and such a pool of liquid is indicated byshading in the lower end of the vessel immediately below zone E.

A conduit 23 is arranged in the form of a ring around vessel H adjacentzone C with a plurality of outlet lines 24 connected to the wall of thevessel and fluidly connecting zone C with conduit 23 which serves as agas collecting ring. Conduit 23 is connected to line 24' whichdischarges into compressor 25. The gas passes from compressor 25 throughline 26 and into drier 21 and is discharged from the drier into line IIwhich serves to return the dried gases to the nozzle assembly l2.

A conduit 28 is arranged to withdraw from a lower portion oi vessel II aside stream which includes both liquid from the pool of quenching liquidand gases from the zone E. Conduit 28 discharges into a vessel 29 whichis arranged to separate into fractions the quenching liquid, polymer andgases withdrawn from vessel II by conduit 28. The gases and vaporscollect in the upper portion of vessel 29, which is designated as zoneF, and are removed from this zone through line it. The gases and vaporsfrom linev 20 are compressed in compressor 2|, pass through line 22 todrier 32 and are discharged through line 24 to line It to be returned tovessel H. A vertically arranged screen ll is placed in vessel 29 to actas a polymer skimmer. A mixture of polymer and quenching liquid isaccumulated in the lower portion of vessel 29. The quenching liquidpasses through screen 35, is withdrawn through line 36 containing pump31 and is returned to the pool of quenching liquid in the bottom oftower. ll. screen 35 may be withdrawn from vessel 29 by any conventionalmeans, such as a screw conveyer.

The compressors 25 and 3| are operated so that zone C is at asubstantially lower pressure than zone A, and zones E and F at apressure substantially below that of zone C. By arran in the pressurediflerential in this manner, th major portion of the gas blanketing thereactant stream is removed from zone C but a small portion of the gaspasses on to zone E and this gas, along with vapors leaving the pool ofquenching liquid, is withdrawn from 'zone E by conduit 28 and passedfrom zone F into line 30 and to compressor 3|. With such an arrangementthe maior portion of the gas used for blanketing the stream of reactantsis maintained quite dry and requires only a small amount of drying invessel 21. On some occasions, it may be desirable to by-pass drier 21and this may be done by opening valve 38 in by-pass line 38 and closingvalve It in line l8. The minor portion of gases removed from zone Fcontain a substantial portion of vapors and require a substantial amountof drying in vessel 33.

In the operation of the present method, it will be understood that theliquid catalyst discharged through inlet line It into nozzle assembly I2is chilled, in accordance with the usual operation of adet reactor, to atemperature in the range oi. to F. Similarly, the oleflnic feed stockdischarged by inlet ll into the nozzle assembly I2 is chilled to atemperature in the range of approximately 120 to -160 F. It will beunderstood that although in the drawing the liquid catalyst is shown asdischarged into inner jet I3 and the oleiinic feed as discharged intothe space between tubes l3 and I l, the position of these two reactantmaterials may be reversed and oletlnic feed stock may be passed intoreaction vessel H by means oi inlet line It and tube l3 and liquidcatalyst may be passed into the reaction vessel by inlet line H. In anyevent, a stream of chilled liquid catalyst and a stream 01 chilledoletlnic feed stock are admixed to form a resultant stream which has anaxis or direction of flow parallel with the axis of reaction vessel IIand this stream is blanketed by the mass of gas' passed into the vesselll through inlet line II and into the space between nozzles l4 and IS.

The stream of gas concentric with the stream oi reactants moves withapproximately the same velocity as the stream of liquid reactants andprevents the spattering or misting of the reactant stream. The velocity01' the reactant stream and the size of the reaction vessel H areproportioned so that by the time the reactant stream enters zone Cpolymer has been formed in the stream of reactants and at least a majorportion of the blanketing stream of gas may be removed from the streamoi reactants without danger of polymer building up on the walls 01' thereaction vessel. Accordingly, the major portion of the blanketing gas isremoved from reaction vessel I l The polymer separated by aosaoss inzone by means of radially extending tubes 24 and collecting ring 28. Theremaining gases and the reactant stream pass from zone C through zone Dand into zone E where the reactants enter the pool of quenching liquidand the polymerization reaction is terminated to produce mime:- of thedesired characteristics.

A slurry of polymer and quenching liquidpasses through outlet line 28 tovessel 29 where the polymer is removed from the quenching liquid throughscreen 35 and the quenching liquid then recycled to vessel. It will beunderstood that as polymer accumulates in vessel 29, it may be removedby suitable means, such as by a screw conveyor, not shown in thedrawing. Gas is removed from gas collecting ring 23 and from zone F invessel 29, recompressed, dried and returned to vessel ll.

It will be seen that until immediately before the reactants enter thepool of quenching liquid. the direction of flow of the blanketing gas isparallel with the flow of the liquid reactants. In other words, thedirection of fiow of the blanketing gas stream is not only parallel withthe direction of flow of the reactant stream in zone A and B but in zone0 gas is removed by the collecting ring 23 so that the direction of flowof the gas remaining in the vessel is not through space surrounded bythe gas until a substantial amount of polymer is formed therein. As asecond step the reactant stream is quenched by bringing it into intimatecontact with a quenching liquid while the gas is removed'so that it willnot interfere with 'the flow of the liquid stream of reactantssurrounded by the concentric stream of gas. The second stepis carriedout at a pressure substantially lower than the first step in order toinsure the removal of gases from the second step at a sumciently rapidrate to prevent any interference with the first step and in order toinsure the absence of quenching liquid vapors in the first step. For

convenience in carrying out these steps it is desirable to employ areaction vessel having at least three zones with the mixing of thestreams of reactant liquids surrounded by a concentric stream of gas andthe formation of a substantial amount of polymer in the first zone, theremoval of a major portion of the surrounding stream of gas in a secondzone and the quenching of the reactants and the removal of the remainingas in a third zone. Inpther words, an elongated I reaction vesseldivided by bafiles into three zones and arranged to maintain the highestpressure in the first zone, a lower pressure in the second zone and astill lower pressure in the third zone may be employed; such a vesselwould correspond to vessel II but including only zones A, C and E. It ispreferred, however, to provide a vessel with at least five zones asshown in the drawing with the reactants and the stream of gas dischargedinto a first zone, a major portion of the gas removed from the thirdzone and the remaining gas removed and quenching conducted in the fifthzone, with a second zone between the first and third zones and a fourthzone between the. third and fifth zones in order to maintain moreeffectively the pressure differential between the first and third zonesand between the third and fifth zones.

' A number of gases may advantageously be used for the purpose offorming the concentric mass of gas around the stream of liquidreactants. Suitable gaseous materials may be hydrogen, methane. ethane,ethylene or mixtures thereof. If desired, these gaseous blanketingagents may be chilled by conventional refrigerating equipment beforethey are discharged into vessel II. The liquids employed in thequenching zone may be those conventional to the art. At the presenttime, water and alcohol are the liquids usually employed as quenchingagents. The amount and temperature of the quenching liquid employed maybe varied over a very wide range but usually itris desirable to employ alarge excess of quenching liquid at a temperature no lower thanatmospheric. v v

Having fully described and illustrated the practice of the presentinvention. what we desire to claim is:

- 1. A method of polymerizing olefins comprising the steps of admixing achilled liquid stream including Friedel-Crafts metallic halide catalystvand a chilled liquid stream including olefin to form a resultant streamunder conditions to cause the formation of polymer, passing theresultant stream of reactants through a first zone to form polymer insaid first stream while in said zone, forming a concentric stream of gasmoving in the same direction and at approximately the same velocity asthe liquid stream around the liquid stream of reactants immediately uponthe formation of said stream, passing the stream of liquid reactants andthe concentric stream of gas into a second zone maintained at a pressuresubstantially below the pressure of the first zone,

removing a major portion of the concentric gaseous stream in said secondzone, passing the liquid reactants and the remaining gases into a thirdzone maintained at a pressure below the second zone, and quenching thereactants in the third zone.

2. A method in accordance with claim 1 in which the olefin isisobutylene.

3. A method in accordance with claim 1 in which the olefin is a mixtureof isobutylene and isoprene.

4. A method of polymerizing olefins including the steps of causing afirst chilled liquid stream including Friedel-Crafts metallic halidecatalyst to flow substantially parallel with a econd chilled liquidstream including olefin, admixing the two streams in space in a firstzone to form a resultant stream having a direction of fiow substantiallyparallel with the direction of fiow or the first and 1 second streamsand maintained under conditions to cause the formation of polymer insaid zone, forming a stream of gas having a direction of flow parallelwith the first and second liquid streams at a velocity approximatelyequal to the velocity of the resultant stream and surrounding the twoliquid streams while being admixed and the resultant stream with saidgaseous stream and maintaining the gaseous stream concentric with theresultant stream in the first zone, passing the resultant liquid streamand the concentric gas stream without a substantial change of directioninto a second zone maintained under a a,sss,osa

pressure substantially below the pressure oi the first zone, removing a.major portion 01' the gas comprising the gaseous stream from the secondzone, passing the resultant liquid stream and the remaining gas withoutsubstantial change of direction irom the second zone to a third zone,intimately mixing the liquid stream with quenching liquid in the thirdzone and removing the remainder of the gas comprising the gaseous streamfrom the third zone.

5. A method in accordance with claim 4 in which the olefin isisobutylene.

6. A method in accordance with claim 4 in which the olefin is a mixtureof isobutylene and isoprene.

7. A method of iorming polymer comprising the steps oi forming a firstchilled liquid stream including Friedel-Crafts metallic halide catalystand alkyl halide, forming a second chilled liquid stream includingisobutylene concentric with the first liquid stream, forming a stream oigas concentric with the second liquid stream, projecting the first andsecond liquid streams in space in a first zone intimately admixing themto form a resultant liquid stream under conditions to form polymer inthe resultant stream while within the first zone, surrounding the firstand second liquid streams on admixture and the resultant stream with theconcentric gas stream moving in the a same direction and atapproximately the same velocity as the resultant liquid stream, passingthe resultant liquid stream and the concentric mainder of the gas streaminto a third zone with- 40 2,375,256

- out substantially changing the direction or flow oi the resultantliquid stream, intimately admixing the resultant liquid stream withquenching liquid in the third zone to terminate rapidly thepolymerization reaction and removing the remainder oi the gas in thegaseous stream from the third zone.

8. A method in accordance with claim 7 in which a fourth zone isinterposed between the first and second zone and a fiith zone isinterposed between the second and third zones and in which the stream ofreactants surrounded by the stream oi gas flows irom the first throughthe fourth to the second zone without substantial change in directionand in which the resultant liquid stream and remainder of the gas in thegaseous stream flows from the second through the fifth to the third zonewithout substantial change in direction oi the resultant liquid stream.

9. A method in accordance with claim 7 in which the gas withdrawn fromthe second zone is compressed and dried to form a first fraction and inwhich the gasswithdrawn from the third zone is compressed and dried toiorm a second fraction and in which the first and second fractions arereturned to the first zone to iorm the concentric stream of gas.

SHERMAN S. SHAFFER. BRADSHAW F. ARMENUI.

REFERENCES CITED The following references are of record in the file oithis patent:

UNITED STATES PATENTS Number Name Date 2,276,893 Thomas Mar. 17, 19422,280,802 Depew Apr. 28, 1942 Soday May 8, 1945

1. A METHOD OF POLYMERIZING OLEFINS COMPRISING THE STEPS OF ADMIXING ACHILLED LIQUID STREAM INCLUDING FRIEDEL-CRAFTS METALLIC HALIDE CATALYSTAND A CHILLED LIQUID STREAM INCLUDING OLEFIN TO FORM A RESULTANT STREAMUNDER CONDITIONS TO CAUSE THE FOMRATION OF POLYMER, PASSING THERESULTANT STREAM OF REACTANTS THROUGH A FIRST ZONE TO FORM POLYMER INSAID FIRST STREAM WHILE IN SAID ZONE, FORMING A CONCENTRIC STREAM OF GASMOVING IN THE SAME DIRECTION AND AT APPROXIMATELY THE SAME VELOCITY ASTHE LIQUID STREAM AROUND THE LIQUID STREAM OF REACTANTS IMMEDIATELY UPONTHE FORMATION OF SAID STREAM, PASSING THE STREAM OF LIQUID REACTANTS ANDTHE CONCENTRIC STREAM OF GAS INTO A SECON ZONE MAINTAINED AT A PRESSURESUBSTANTIALLY BELOW THE PRESSURE OF THE FIRST ZONE, REMOVING A MAJORPORTION OF THE CONCENTRIC GASEOUS STREAM IN SAID SECON ZONE, PASSING THELIQUID REACTANTS AND THE REMAINING GASES INTO A THIRD ZONE MAINTAINED ATA PRESSURE BELOW THE SECOND ZONE, AND QUENCHING THE REACTANTS IN THETHIRD ZONE.